Arthroplasty-associated malignant fibrous histiocytoma: two case reports.

AIMS: Sarcoma localized to the site of an arthroplasty procedure is a rare occurrence, and detailed histological depictions and descriptions are limited. We report the clinicopathological findings in two cases of arthroplasty-associated malignant fibrous histiocytoma (MFH) and review the literature. METHODS AND
RESULTS: The patients were an elderly man and woman. Medical histories, radiographs and slides were reviewed. Immunohistochemistry, electron microscopy, cytogenetics, and electron dispersion spectroscopy were performed in one case. Both were destructive femoral bone tumours that appeared 2 and 8 years post-total hip arthroplasty, and pursued aggressive clinical courses. The histology was similar in both tumours, consisting of high-grade, pleomorphic sarcoma with numerous osteoclastic giant cells, prominent phagocytic activity, and entrapped particles of bone cement. Literature review disclosed 14 previous reports of arthroplasty-associated MFH, representing the most common phenotype. A number of materials and factors related to arthroplasty procedure, such as metal corrosion, wear debris, osteonecrosis, and chronic inflammation, have been implicated as causative agents.
CONCLUSIONS: Arthroplasty-associated MFH is a rare and aggressive tumour. Although the aetiology remains unclear, the small number of arthroplasty-associated sarcomas compared with the large number of joint replacement operations performed over the past four decades suggests a coincidental as opposed to a causal relation.